net/l3mdev/l3mdev.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * net/l3mdev/l3mdev.c - L3 master device implementation
   4  * Copyright (c) 2015 Cumulus Networks
   5  * Copyright (c) 2015 David Ahern <dsa@cumulusnetworks.com>
   6  */
   7
   8 #include <linux/netdevice.h>
   9 #include <net/fib_rules.h>
  10 #include <net/l3mdev.h>
  11
  12 /**
  13  *      l3mdev_master_ifindex - get index of L3 master device
  14  *      @dev: targeted interface
  15  */
  16
  17 int l3mdev_master_ifindex_rcu(const struct net_device *dev)
  18 {
  19         int ifindex = 0;
  20
  21         if (!dev)
  22                 return 0;
  23
  24         if (netif_is_l3_master(dev)) {
  25                 ifindex = dev->ifindex;
  26         } else if (netif_is_l3_slave(dev)) {
  27                 struct net_device *master;
  28                 struct net_device *_dev = (struct net_device *)dev;
  29
  30                 /* netdev_master_upper_dev_get_rcu calls
  31                  * list_first_or_null_rcu to walk the upper dev list.
  32                  * list_first_or_null_rcu does not handle a const arg. We aren't
  33                  * making changes, just want the master device from that list so
  34                  * typecast to remove the const
  35                  */
  36                 master = netdev_master_upper_dev_get_rcu(_dev);
  37                 if (master)
  38                         ifindex = master->ifindex;
  39         }
  40
  41         return ifindex;
  42 }
  43 EXPORT_SYMBOL_GPL(l3mdev_master_ifindex_rcu);
  44
  45 /**
  46  *      l3mdev_master_upper_ifindex_by_index - get index of upper l3 master
  47  *                                             device
  48  *      @net: network namespace for device index lookup
  49  *      @ifindex: targeted interface
  50  */
  51 int l3mdev_master_upper_ifindex_by_index_rcu(struct net *net, int ifindex)
  52 {
  53         struct net_device *dev;
  54
  55         dev = dev_get_by_index_rcu(net, ifindex);
  56         while (dev && !netif_is_l3_master(dev))
  57                 dev = netdev_master_upper_dev_get(dev);
  58
  59         return dev ? dev->ifindex : 0;
  60 }
  61 EXPORT_SYMBOL_GPL(l3mdev_master_upper_ifindex_by_index_rcu);
  62
  63 /**
  64  *      l3mdev_fib_table - get FIB table id associated with an L3
  65  *                             master interface
  66  *      @dev: targeted interface
  67  */
  68
  69 u32 l3mdev_fib_table_rcu(const struct net_device *dev)
  70 {
  71         u32 tb_id = 0;
  72
  73         if (!dev)
  74                 return 0;
  75
  76         if (netif_is_l3_master(dev)) {
  77                 if (dev->l3mdev_ops->l3mdev_fib_table)
  78                         tb_id = dev->l3mdev_ops->l3mdev_fib_table(dev);
  79         } else if (netif_is_l3_slave(dev)) {
  80                 /* Users of netdev_master_upper_dev_get_rcu need non-const,
  81                  * but current inet_*type functions take a const
  82                  */
  83                 struct net_device *_dev = (struct net_device *) dev;
  84                 const struct net_device *master;
  85
  86                 master = netdev_master_upper_dev_get_rcu(_dev);
  87                 if (master &&
  88                     master->l3mdev_ops->l3mdev_fib_table)
  89                         tb_id = master->l3mdev_ops->l3mdev_fib_table(master);
  90         }
  91
  92         return tb_id;
  93 }
  94 EXPORT_SYMBOL_GPL(l3mdev_fib_table_rcu);
  95
  96 u32 l3mdev_fib_table_by_index(struct net *net, int ifindex)
  97 {
  98         struct net_device *dev;
  99         u32 tb_id = 0;
 100
 101         if (!ifindex)
 102                 return 0;
 103
 104         rcu_read_lock();
 105
 106         dev = dev_get_by_index_rcu(net, ifindex);
 107         if (dev)
 108                 tb_id = l3mdev_fib_table_rcu(dev);
 109
 110         rcu_read_unlock();
 111
 112         return tb_id;
 113 }
 114 EXPORT_SYMBOL_GPL(l3mdev_fib_table_by_index);
 115
 116 /**
 117  *      l3mdev_link_scope_lookup - IPv6 route lookup based on flow for link
 118  *                           local and multicast addresses
 119  *      @net: network namespace for device index lookup
 120  *      @fl6: IPv6 flow struct for lookup
 121  *      This function does not hold refcnt on the returned dst.
 122  *      Caller must hold rcu_read_lock().
 123  */
 124
 125 struct dst_entry *l3mdev_link_scope_lookup(struct net *net,
 126                                            struct flowi6 *fl6)
 127 {
 128         struct dst_entry *dst = NULL;
 129         struct net_device *dev;
 130
 131         WARN_ON_ONCE(!rcu_read_lock_held());
 132         if (fl6->flowi6_oif) {
 133                 dev = dev_get_by_index_rcu(net, fl6->flowi6_oif);
 134                 if (dev && netif_is_l3_slave(dev))
 135                         dev = netdev_master_upper_dev_get_rcu(dev);
 136
 137                 if (dev && netif_is_l3_master(dev) &&
 138                     dev->l3mdev_ops->l3mdev_link_scope_lookup)
 139                         dst = dev->l3mdev_ops->l3mdev_link_scope_lookup(dev, fl6);
 140         }
 141
 142         return dst;
 143 }
 144 EXPORT_SYMBOL_GPL(l3mdev_link_scope_lookup);
 145
 146 /**
 147  *      l3mdev_fib_rule_match - Determine if flowi references an
 148  *                              L3 master device
 149  *      @net: network namespace for device index lookup
 150  *      @fl:  flow struct
 151  */
 152
 153 int l3mdev_fib_rule_match(struct net *net, struct flowi *fl,
 154                           struct fib_lookup_arg *arg)
 155 {
 156         struct net_device *dev;
 157         int rc = 0;
 158
 159         rcu_read_lock();
 160
 161         dev = dev_get_by_index_rcu(net, fl->flowi_oif);
 162         if (dev && netif_is_l3_master(dev) &&
 163             dev->l3mdev_ops->l3mdev_fib_table) {
 164                 arg->table = dev->l3mdev_ops->l3mdev_fib_table(dev);
 165                 rc = 1;
 166                 goto out;
 167         }
 168
 169         dev = dev_get_by_index_rcu(net, fl->flowi_iif);
 170         if (dev && netif_is_l3_master(dev) &&
 171             dev->l3mdev_ops->l3mdev_fib_table) {
 172                 arg->table = dev->l3mdev_ops->l3mdev_fib_table(dev);
 173                 rc = 1;
 174                 goto out;
 175         }
 176
 177 out:
 178         rcu_read_unlock();
 179
 180         return rc;
 181 }
 182
 183 void l3mdev_update_flow(struct net *net, struct flowi *fl)
 184 {
 185         struct net_device *dev;
 186         int ifindex;
 187
 188         rcu_read_lock();
 189
 190         if (fl->flowi_oif) {
 191                 dev = dev_get_by_index_rcu(net, fl->flowi_oif);
 192                 if (dev) {
 193                         ifindex = l3mdev_master_ifindex_rcu(dev);
 194                         if (ifindex) {
 195                                 fl->flowi_oif = ifindex;
 196                                 fl->flowi_flags |= FLOWI_FLAG_SKIP_NH_OIF;
 197                                 goto out;
 198                         }
 199                 }
 200         }
 201
 202         if (fl->flowi_iif) {
 203                 dev = dev_get_by_index_rcu(net, fl->flowi_iif);
 204                 if (dev) {
 205                         ifindex = l3mdev_master_ifindex_rcu(dev);
 206                         if (ifindex) {
 207                                 fl->flowi_iif = ifindex;
 208                                 fl->flowi_flags |= FLOWI_FLAG_SKIP_NH_OIF;
 209                         }
 210                 }
 211         }
 212
 213 out:
 214         rcu_read_unlock();
 215 }
 216 EXPORT_SYMBOL_GPL(l3mdev_update_flow);